In conventional automatic milk extraction processes, a so-called nominal vacuum is applied to the milk discharge line which is fixedly installed in the stable and in the milking palor, respectively. This nominal milking vacuum is used for extracting milk from the teat on the one hand, and for discharging the extracted milk on the other. How high the vacuum actually is, which is effective below the teat at certain moments, depends on a plurality of factors, especially, however, on the cross-section of the long milk hose on the one hand and on the magnitude of the milk flow from a cow, which is extracted from the teat, on the other. Hence, long milk hoses adapted to the maximum cow milk flow to be expected should, in principle, be used for an optimum adjustment of the vacuum below the teat during the suction and relief cycles. In view of the fact that, in most cases, several cows are milked successively making use of the same milking unit, the inevitably resulting circumstances will not permit optimum milking. If long milk hoses having an insufficient interior cross-section, which may be the optimum milk hoses for a specific cow having a low flow of milk, are e.g. used, this may, on the one hand, have the effect that, for the next cow having a higher flow of milk, the milk discharge capacity is not sufficiently high so that an undesirable accumulation of milk occurs, and, on the other hand, it may have the effect that the milking vacuum below the teat becomes so low that the pressure relief of the teat will no longer be sufficient or that, in extreme cases, the teat cups will even fall off. If, however, long milk hoses having a very large interior cross-section, which would be optimally adapted to cows having a very high flow of milk, are used, the use of this milking unit for cows having a low flow of milk may have the effect that an excessively high vacuum occurs below the teat during the relief cycle and this would necessarily cause damage to the teat in the long run. In order to achieve the best possible adaptation, long milk hoses having at least nine different interior cross-sections are therefore available on the market, viz. hoses having interior diameters between 8 and 16 mm, the difference from one hose to the next being 1 mm.
Hence, it is the object of the present invention to improve this situation.